THE DRO-GENITAL SYSTEM 



The uro-genital apparatus, or apparatus uro-genitalis, consists 

 of two groups of organs: the urinary and the genital. The former 

 elaborate and remove the chief excretory fluid, the urine; and the 

 latter serve for the formation, development, and expulsion of the 

 products of the reproductive glands. 



THE UBINARY APPARATUS (Fig. 50 and Fig. 51)- 



The urinary apparatus of the bird consists of two kidneys, from 

 each of which a ureter extends and empties into the cloaca. 



The Elidneys. Location. — The kidneys are located in excavations 

 in the pelvic roof. They are related internally with the posterior 

 aorta and vena cava, supero-intemaUy with the lumbo-sacral ver- 

 tebrae and superiorly and supero-extemally with the iUum. The 

 abdominal visceral organs he below the kidneys. The kidneys are 

 external to or above the peritoneum. 



Shape. — In the fowl ofi average size the kidneys are 2}^, inches 

 long and are made up of three irregular lobes. The anterior lobe 

 is usually the largest and the middle the smallest. The anterior 

 border of the first lobe is located opposite the last true dorsal articu- 

 lation. The anterior lobe is caUed the anterior pelvic or ilio-lmnbar 

 lobe, the middle the middle pelvic or iHo-sacral lobe, and the posterior 

 the posterior pelvic lobe. 



Structure. — The whole kidney has a fine transparent covering. 

 The dark, brownish-red parenchyme can be seen through this mem- 

 brane. It has a blood vascular system and a urinary tubular sys- 

 tem. The larger arteries, the veins, and the nerves pass between the 

 lobules, and the smaller vessels between the tubules. These form 

 fine network or plexuses. The lymphatic vessels are very few, and 

 are mainly found on the surface. The kidneys are pierced in their 

 posterior third by the external iUac artery and at about its middle 

 by the venous branches forming the posterior vena cava. 



The lobes are made up of lobules, which are plainly perceptible 

 from the external surface. Each lobule is apparently a unit within 



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